Flower profile

Bristle thistle

Cirsium horridulum

Native in the lower 48

Bristle thistle is a wildflower that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 6 states, and across the U.S. it's most often seen in bloom in March–May.

22states

6of our state lists

23,430U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina

Quick look

Cirsium horridulum, called bristly thistle, purple thistle, or yellow thistle is a North American species of plants in the tribe Cardueae within the family Asteraceae. It is an annual or biennial.100 The species is native to the eastern and southern United States from New England to Florida, Texas, and Oklahoma as well as to Mexico, Belize, Guatemala, Honduras, and the Bahamas.
From Wikipedia's article Cirsium horridulum, CC BY-SA 4.0.

It belongs to the Asteraceae family. ^iNaturalist
USDA PLANTS describes it as an herb (forb) with a annual, biennial life cycle. ^{USDA PLANTS}
USDA PLANTS lists it as native in the lower 48 states and records it in 22 states. ^{USDA PLANTS}
NatureServe lists it as native to Florida, Louisiana, Georgia, Alabama, Mississippi and South Carolina. ^NatureServe
In Florida, most iNaturalist sightings of it in flower come in February–May. ^iNaturalist
In Louisiana, most iNaturalist sightings of it in flower come in March–May. ^iNaturalist
iNaturalist has 6,961 research-grade sightings of it in Florida, ranking #15 among the 110 flowers on our Florida list. ^iNaturalist
iNaturalist has 2,367 research-grade sightings of it in Louisiana, ranking #4 among the 109 flowers on our Louisiana list. ^iNaturalist
iNaturalist has 1,895 research-grade sightings of it in Georgia, ranking #32 among the 111 flowers on our Georgia list. ^iNaturalist

Bristle thistle gift ideas

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When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (3,312 records)

Bloom time in each of our 6 states

State	Type	Peak bloom	Sightings*
Florida	Native	February–May	6,961
Louisiana	Native	March–May	2,367
Georgia	Native	March–May	1,895
Alabama	Native	March–May	1,314
Mississippi	Native	March–May	1,005
South Carolina	Native	March–June	844

Conservation status

Federal (U.S. ESA): Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. ^{USFWS ECOS}
NatureServe global: G5 Secure worldwide. ^NatureServe
Florida: Not listed Not on Florida Regulated Plant Index (Fla. Admin. Code 5B-40.0055). NatureServe: S4, apparently secure in Florida. ^{FAC 5B-40.0055}
Louisiana: No list Louisiana has no state list of endangered or threatened plants separate from the federal list, so we show federal status and NatureServe's Louisiana ranks. NatureServe: SNR, not yet ranked in Louisiana.
Georgia: Not listed Not on Georgia protected plants (Ga. Comp. R. & Regs. 391-4-10-.09; a 2026 update is proposed). NatureServe: S5, secure in Georgia. ^{Ga. R. 391-4-10-.09}
Alabama: No list Alabama has no state law listing endangered or threatened plants, so we show NatureServe's Alabama ranks instead. NatureServe: SNR, not yet ranked in Alabama.
Mississippi: No list Mississippi has no state law listing endangered or threatened plants, so we show NatureServe's Mississippi ranks instead. NatureServe: SNR, not yet ranked in Mississippi.
South Carolina: No list South Carolina has no state law listing endangered or threatened plants, so we show NatureServe's South Carolina ranks instead. NatureServe: SNR, not yet ranked in South Carolina.
Rare elsewhere: Other states where NatureServe ranks it rare or missing: CT (S1), ME (SH), PA (S1). (S1 critically imperiled, S2 imperiled, SH possibly extirpated, SX presumed extirpated.)

Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.

Can you eat it?

For peopleNot well documented

None of the sources we checked (NC State Extension (no edibility or poison notes on its page), USDA PLANTS) say whether it's edible or poisonous for people. ^{NC State Extension}

For petsNot well documented

It isn't on the ASPCA plant list, and NC State Extension doesn't flag it for pets.

🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.

Where does it grow?

USDA PLANTS records bristle thistle in 22 states.

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recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alabama, Arkansas, Connecticut, Delaware, Florida, Georgia, Louisiana, Maine, Maryland, Massachusetts, Mississippi, New Hampshire, New Jersey, New York, North Carolina, Oklahoma, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Virginia.

Florida counties with USDA records: Alachua, Brevard, Broward, Charlotte, Citrus, Collier, Dixie, Escambia, Flagler, Hardee, Hendry, Hernando, Highlands, Hillsborough, Indian River, Lake, Lee, Levy, Manatee, Marion, Martin, Miami-Dade, Monroe, Nassau, Okaloosa, Okeechobee, Osceola, Palm Beach, Pasco, Pinellas, Polk, Putnam, Sarasota, Seminole, St. Lucie, Sumter, Taylor, Volusia, Wakulla, Walton.

Louisiana counties with USDA records: Acadia, Allen, Ascension, Assumption, Beauregard, Bienville, Caddo, Calcasieu, Caldwell, Cameron, Catahoula, Claiborne, Concordia, De Soto, East Baton Rouge, East Carroll, East Feliciana, Evangeline, Franklin, Grant, Iberia, Iberville, Jackson, Jefferson, Jefferson Davis, LaSalle, Lafayette, Lafourche, Lincoln, Livingston, Madison, Morehouse, Natchitoches, Orleans, Ouachita, Plaquemines, Rapides, Red River, Richland, Sabine, St. Bernard, St. Charles, St. Helena, St. James, St. John the Baptist, St. Landry, St. Martin, St. Mary, St. Tammany, Tangipahoa, Tensas, Terrebonne, Union, Vernon, Washington, Webster, West Carroll, West Feliciana, Winn.

Georgia counties with USDA records: Baldwin, Bartow, Berrien, Brooks, Camden, Charlton, Clarke, Colquitt, Dodge, Elbert, Glynn, Greene, Harris, Hart, Jasper, Jones, Laurens, Liberty, McIntosh, Monroe, Morgan, Oglethorpe, Pike, Putnam, Spalding, Talbot, Taylor, Warren, Washington, Wilkes.

More Florida flowers

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White beggarticks

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Sources

USDA, NRCS. PLANTS Database, profile CIHO2.
iNaturalist, Cirsium horridulum: taxonomy, research-grade observation counts and “Flowering” annotations, retrieved October 17, 2026.
Wikipedia, Cirsium horridulum (lead quoted under CC BY-SA 4.0).
Florida: Florida Regulated Plant Index (Fla. Admin. Code 5B-40.0055).
Florida: Florida Noxious Weed List (Fla. Admin. Code 5B-57.007).
Georgia: Georgia protected plants (Ga. Comp. R. & Regs. 391-4-10-.09; a 2026 update is proposed).
Alabama: Alabama noxious weeds (Ala. Admin. Code r. 80-10-14-.04).
Mississippi: Mississippi Noxious Weed List (2 Miss. Code R. 1-3-01-136.01).
South Carolina: South Carolina State Plant Pest List, plants (S.C. Code Regs. 27-135; Clemson Dept. of Plant Industry).
USFWS, ECOS species database (ESA listing check), October 17, 2026.
NatureServe Explorer, Cirsium horridulum (global and state ranks).
Edibility and toxicity: NC State Extension.
Photo: Nonbinary-Naturalist via iNaturalist · CC0 · resized.